Float valve



Patented Sept. 21, 1943 UNITED STATES Maarten M'. Verheul, Houston, Tex.

Application mm, 1941, Serial Nb. 404,149" (01. 137-69) 16 Claims.

This invention relates to back pressure valves and has for its general object the provision of a back pressure valve suitable for use as a float valve for a well casing, or the like.

' In the past, various types of back pressure valves have been employed at the bottom of, or at some point within a casing, or the like; as it is being lowered into a well. The purpose of such valve is to prevent flow of fluid, with which such wells are usually filled, into the lower end f the casing. The casing is thu maintained either partially or wholly empty of liquid, with the resuit that the liquid in the well exerts a substantial buoyant influence on the casing and relieves the hoisting apparatus at the surface of the ground of a large portion of the weight of the casing which it would otherwise have to sustain.

After such casings have been located in their desired position within a well and have been cemented or otherwise secured in place, it becomes.

necessary to remove the valve'or valves, thus employed in floating the casing For the most part such valves have been removed by drilling them out with a suitable drilling tool lowered through the casing. Difiiculty has been experienced, however, due to the fact that most such valves employing moving parts have necessarily been made of a relatively strong and hard material, diflicult to drill with ordinary drilling tool. Furthermore, most such valves have parts which are rotatable with respect to the casing when the valves are in place and when these partsare encountered b a drilling tool and the drilling tool rotates, the parts will merely rotate and will not be removed or broken up by the drilling tool.

In still other instances, such valves have been so formed that when partially drilled out, relatively large parts would, be left intact to fall to the bottom of the hole and there interfere with further drilling operation, and those parts have in most instances, due to the construction of the valve involved, been necessarily of such a nature that they could not be bro-ken up readily by the ordinary drilling tools.

In view of the foregoing, it is an object of this invention to provide a float valve which may be readily incorporated into 1 an ordinary casing structure and yet which may be easily removed by the ordinary drilling tool when so desired.

Another object of this invention is to providev such a structure which has no rigid moving parts and no parts which are necessarily of suchhardness that they will be difiicult to drill up with ordinary drilling, tools. i

Another object of thisinventioni to provide .tion, taken in connection. with ing drawing wherein are set forth byway of ex-' ample and illustration, two embodiments of this such. a structure which will not require any. spe

-'cial form of easing or. casingcoupling for the purpose of-receiving it. v r

. Another object of thisrinventionis to provide such a structure in which there are no parts which can rotate withthedrilling tool whenit is desired to break upthe valve structure by means ofadrilling tool. i y

Other objects and advantage of this invention will become apparent-from the followingdescripthe accompanyinvention.

In the drawing: 1 v w Fig l is a view in longitudinal cross section illustrating a valve constructed in accordance with this invention;. g

Fig. 2'illustrates a transverse cross section through the structure shown in Figure -l,;the

same being taken along the line 2-2 of Figure; 1; Fig; 3 is a view 'similarito Figure l but showing amodification; l

Fig. 4 is a view similar toFigure 2 but taken along the line 4-4 of Figure 3.

' The valves constructed in accordance with this invention are adapted to be mountedwithin' a collarl which is an ordinary casing collar having joints of casing 2 and 3 respectively-threaded into its opposite ends.

. .rThe valve, as illustrated in Figures 1", and 2 consists of a. bod member--4'which may bereferred to as a spider, a mandrel 5, and flexible sealing; cup 6. The spider, in theqform shown, consists of an annular portion disposedabout .the central .axis of the casing and having circumferentiallyspaced radially extending arms 'l, the outer ends of which are formedwith threads 8 adapted to fit thethreaded intermediate section of the casing collar l.

Itwill beapparent" that this spider is intended to be threaded intothe col lar l and to occupy the space which normally exists within the collar between the two casing 'joint 2 and 3. The openings between the arms 'l'are adapted topermit .the downward flow of slush or other fluid when sodesire The interior of theLannular, portion of the spider is also threaded-asishown at 9 toreceive the threads llloon the mandrel 5. It noted that the threads .10 in: thisinstance are will 7 be lefthand threads described. I The mandrel 5, is provided with a, lower enlargement H ,forming, a head withxarelatively for a purpose to be presently smooth cylindrical portion 12 between the, head ,WhiCh may threads on the 2 ll and the thread [0, and with a relatively smooth cylindrical portion l3 above the thread H3. The cylindrical portion 12 is preferably slightly larger in diameter than the threads [0 and the cylindrical portion is slightly of smaller diameter than thread Ill.

Surrounding the portion ll of the mandrel is the base portion 14 of the flexible cup 6. This cup extends from such base portion l4 outwardly and downwardly and terminates in a relatively Very flexible sealing lip I5, which. is of such a diameter that it is normally pressed against the interior of the casing joint 3 to form a seal therewith. It will be appreciated that the cup 6 is prevented from coming off the mandrel 5 by thehead H. The cup is positively held against upward movement by virtueof its abutment against the cup seat IE on the lower surface of theannular part of spider 4.

It will be seen from the foregoing that the valve just described may be readily'inserted: into any ordinary casing coupling and that the lip l5 of the sealing cup 6 will prevent any upward flow. through the casing. The mandrel. may be properly adjusted by means of a wrench. or, tong, be engaged with the part It of the mandrelprior tothe time thatthecasingjoint 2 is threaded into place within collar I. Because .of. the location of the spider l and its connection? with the casing collar I, this-spider cannot be rotated. to the right when it is engaged .With an ordinarydrilling tool for the purpose of. breaking up the valve. Itsright hand rotation will-be positively limited by the engagement of thearms I with the upper end of the casing joint 3; Likewise, the mandrel 5v will be prevented frommtating to the right during such drill operation. by virtue of the left hand thread 10. i- Thus, as. the drill tends to rotate themandrelto the right the mandrel may be rotated to the right. onlmuntil the part [2 engages the lower surfaceoof the spiderv .4. Thereafter the. mandrel will .remain stationary and rotation of the drilling tool will -serve to break it up. i l t The spider and the mandrel are both. formed preferably of a readily drillable material, such as. phenolic condensation products, or other well known plastics. Since none of the parts move with respect to each other, there is no need that these parts be especially hard so that they would off-er resistanceto being drilled." On thetother hand, these-parts are preferably relatively ifriable andeasilybroken, having only sufiicient strength to enable them to withstand force .due, tothe hydrostatic pressures encountered in a well.

Itvvill be seen, furthermore, from below such a valvewill tend to seal the lip l5 all themore tightly against the casing wall but that pressure from above the valve. may easily force itself past this flexible lip so that, down; flow may take place through the casing whenever desired. Such down flow may freely pass between the arms .1 of the spider.

Referring now to the form shown in Figure 3 the principles involved are substantially the same. as those shown in the form of Figure l. Inthis form, however, the spider 4.-a has arms 1-! threaded on theirouter ends at 8-.-a to fit the interior of coupling l. Themandrel 5.- -a has.its.head lla on its upper end insteadof'on its lower endand:is threadedly engaged with the interior of spider 4a by,means of right hand-threads Ill-an The spider 4--a has its annular portion extending upwardlysomewhat above the arms 1-a and:provides aishoulthat fluid pressure der at its upper end for the purpose of limiting downward movement of sealing cup 6-a. The base M-a of the sealing cup 6-a embraces the cylindrical portion I2-a of the mandrel which lies between the spider and the head ll-a, and the flexible lip l5-a of this sealing cup forms a seal against the interior of the upper casing joint 2. The head I 1-11 on the mandrel provides an abutment lfi--a that prevents any upward movement of the cup 6 -0,,

It will be perceived that the-form just described operates in substance much the same as the form shown in Figure 1 except that the sealing cup 6--a is disposed above the spider instead of-below it as in Figure 1, and the lip I5-a forms a seal against the interior of the casing joint 2 instead of the casing joint 3.

' When a drillgis engaged with the valve shown in Figure 3 for the purpose of breaking it up, it will first engage the mandrel head I Ia and will tend to rotatathis mandrelto th i h Ri hand. rotation. of, the. mandrel with respect to the s iderlea, will. cease, howe e w en the threads Iii-dare fully engaged; Likewise, righthand. rotation of. the spider 4-.a with respect to h casi w l. ease! when the-arm 7-11 of. the spider engages. the upper end of thecasing; joint .3, The-dri-ll=may. thenhreahupthe variQll parts and: it is to.be noted in thisin an e h t the last part. to be broken up,,wil1= be spider after the other artshave been. demclisbedb drilling. v v

Haying described myinven iQnL i la-im:

1 In a casing float: valve; aspider; having an annular, part with arms projectineiradially t e e.- from, said armsobcing thre dfld; to, en a e the threads in a. casing coupling between-theends of two .j oints of r casing threaded, thereto, Said nn lar part havin internal threads, at mandre threadedlyengaging:saidclastmentionedthreadin the spider and having ahead athereonspaced sub.- stantiallyirom saidespider with asmoothzone adaptedito:receivetongs, or thalike, andra flexible cuplshaped valve.memher surrounding said mandrel; and'havingalipelike edge yieldably en. gaging the inner surface of one of. said casin joints adjacent said coupling. tolclose the same against flow in Y one direction but capable of flex -ing under pressure to permit flow in the other :di-

rection.

2; Ina casing float-valve, a spider member. hav, ing anannularpart with armsiprojecting:radially therefrom, said arms beingthreaded to-engage the threads of a casing coupling between the ends of two jointscf casing threaded =thereto, said annular part having internal threads and I a mandrel member threadedly engaging a said last mentioned threads 4 in the spider, and having a head thereon-spaced from said-spider, apart of said mandrel spaced substantially. from said spider having a smooth zone adapted to-receive tongs, and a'flexi-blecup-shaped valve member surrounding said mandrel and-having a-lip -lilce edge yieldably engaging the inner 'surface of the-casing joint'adjaoent the coupling to close-the same against flow in'one direction, but capable of flexingunder pressure -to permit flow in the opposite direction; one of'saidmembers having arr-annular abutmentformed-thereon shaped-to provide a seat for the convex portion of saidsealingcup and limit theupward movement thereof.-

3.: In-a-casing-fleat-valve, a spider havingan aimular partwitharms projecting radially therefrom, said arms beingthreaded on their outer endstorengage the threads of a casing'coupling between the ends of two joints of easing threaded thereto, said annular part havinginternal threads, a mandrel threadedly engaging said last mentioned threads in the spider and having a head thereon spaced from said spider and a smooth zone spaced substantially from said spider adapted to receive tongs, and a flexible cup shaped valve member surrounding said mandrel, and having a lip-like edge yieldably engaging the inner surface of one of said casing joints engaging said coupling to close the same against flow in one direction, but capable of flexing under pressure to permit flow in the other direction, said mandrel having its head formed with an annular surface receiving and providing a seat for said cup and preventing upward movement thereof.

4. In a casing float valve, a spider having an annular part with arms projecting radially therefrom, said arms being threaded on their outer ends to engage the threads of a casing coupling between the ends of two joints of casing threaded thereto, said annular part having internal threads, a mandrel threadedly engaging said last mentioned threads in the spider and having a head thereon spaced from said spider and a smooth zone spaced substantially from said spider adapted to receive tongs and a flexible cup shaped valve member surrounding said mandrel, and having a lip-like edge yieldably engaging the inner surface of one of said casing joints enga in said coupling to close the same against flow in one direction, but capable of flexing under pressure to permit flow in the other direction, said spider having its lower surface receiving and providing a seat for said cup and preventing upward movement thereof.

5. In a casing float valve, a spider having an annular part with arms projecting radially therefrom, said arms being threaded on their outer ends to engage the threads of a casing cou pling between the ends of two joints of casing threaded thereto, said annular part having internal threads, a, mandrel threaded into said internally threaded part on the spider from below the same and having a head thereon spaced below said spider and a smooth zone projecting a substantial distance above said spider, adapted to receive tongs, and a flexible cup shaped valve member surrounding said mandrel and having a lip-like edge yieldably engaging the inner surface of one of said casing joints engaging said coupling to close the same against flow in one direction, but capable of flexing under pressure to permit flow in the other direction.

6. In a casing float valve, a spider threaded exteriorly to engage the threads of a casing coupling between the ends of two casin joints threaded thereto, said spider being also threaded internally, last mentioned thread in the spider and having a head thereon spaced from said spider, the threaded engagement between said mandrel and spider being such that a rotation of said mandrel in a clockwise direction, looking in the direction of flow will not disengage said mandrel from said spider, and a flexible cup shaped valve member surrounding said mandrel between said spider and vsaid head on the mandrel, and having a lip-like 7. In a casing float valve, a spider threaded exteriorly to engage the threads of a casing .coupling betwen the ends of two joints of casing threaded thereto, said spider also having internal threads, a mandrel threadedly engagin said internal threads in the spider, and having ahead thereon spaced below said spider, and a part projecting above said spider, the threaded engagementbetween said mandrel and said spider comprising left hand threads and a flexible cup shaped valve member surrounding said mandrel, and having a lip-like edge yieldably' engaging the inner surface of one of said casing joints engaging said coupling to close the same against flow in one direction, but capable of flexing under pressure to permit flow in the other direction.

8. In a casing float valve, -a spider threaded exteriorly to engage the threads of a casing coupling between the ends of two joints of easing threaded thereto, a mandrel engaging said spider and secured thereto in a position concentric with respect to said spider, means for preventing said mandrel from rotating in a right hand direction, as seen from above, when fully engaged and secured to said spider and a flexible cup shaped valve member surrounding said mandrel, and

having a lip-like edge yieldably engaging the inner surface of one of saidcasing joints engaging said couplin to close the same against flow in one direction.

9. In a casing float valve, a spider, means for mounting said spider in a casing coupling between two joints of casing threaded thereto, a part of said spider engaging the end of one of said casing joints upon rotation of said spider with respect to said coupling in one direction to limit rotation thereof in said one direction, a mandrel, means on said mandrel and spider for securing said mandrel to said spider and preventing rotation of; said mandrel in the same direction when fully engaged, and a flexible cup shaped valve member carried by said mandrel and having a lip-like edge yieldably engaging the inner surface of one of said casing joints engaging said coupling, to close the same against flow in one direction.

10. In a casing float valve, a spider, means for securing said spider in a casing coupling between I two joints of casing threaded thereto, a part of said spider engaging the end of one of said casing joints when rotated in a right hand direction with respect to said coupling as seen from above amandrel threadedly engaging said to limit such right hand rotation, a mandrel threaded into said spider from below by a, left hand threaded engagement and a flexible cup shaped valve member surrounding said mandrel and having a lip-like edge yieldably engaging the V inner surface of one of said casing joints engaging said coupling to close the same against flow in one direction. i I MAARTEN M. VERHEUL. 

